Learning robust and accurate rules for device classification from clusters of devices

ABSTRACT

In various embodiments, a device classification service obtains traffic telemetry data for a plurality of devices in a network. The service applies clustering to the traffic telemetry data, to form device clusters. The service generates a device classification rule based on a particular one of the device clusters. The service receives feedback from a user interface regarding the device classification rule. The service adjusts the device classification rule based on the received feedback.

RELATED APPLICATION

The present application is a continuation of U.S. application Ser. No.16/459,834, filed on Jul. 2, 2019, which claims priority to U.S.Provisional Patent Application No. 62/860,243, filed on Jun. 11, 2019,both entitled “LEARNING ROBUST AND ACCURATE RULES FOR DEVICECLASSIFICATION FROM CLUSTERS OF DEVICES” by Tedaldi et al., the contentsof each which are incorporated by reference herein.

TECHNICAL FIELD

The present disclosure relates generally to computer networks, and, moreparticularly, to learning robust and accurate rules for deviceclassification from clusters of devices.

BACKGROUND

An emerging area of interest in the field of computer networking is the“Internet of Things” (IoT), which may be used by those in the art torefer to uniquely identifiable objects/things and their virtualrepresentations in a network-based architecture. In particular, the nextfrontier in the evolution of the Internet is the ability to connect morethan just computers and communications devices, but rather the abilityto connect “objects” in general, such as lights, appliances, vehicles,window shades and blinds, doors, locks, etc.

As more non-traditional devices join the IoT, networks may eventuallyevolve from a bring-your-own-device (BYOD) model to a model that enablesbring-your-own-thing (BYOT), bring-your-own-interface (BYOI), and/orbring-your-own-service (BYOS) paradigms. In other words, as the IoTgrows, the number of available services, etc., will also growconsiderably. For example, a single person in the future may transportsensor-equipped clothing, other portable electronic devices (e.g., cellphones, etc.), cameras, pedometers, or the like, into an enterpriseenvironment, each of which may attempt to access the wealth of new IoTservices that are available on the network.

From a networking perspective, the network can automatically configureaccess control policies, other security policies, and the like, if thedevice type of a particular device is known to the network. For example,the network may limit a particular type of sensor to only communicatingwith its supervisory device. Typically, this classification is made byobserving the behavior of the device during a short period of time afterjoining the network (e.g., the first minute) and applying a deviceclassification rule to the observed behavior.

Typically, device classification rules today are curated by humanexperts and manually defined. Consequently, testing has shown that up to40% of devices today are classified as being of an unknown device type.As disclosed herein, the recent proliferation of machine learningtechniques now makes it possible to automate the rule creation process,which can significantly reduce this percentage. However, verificationand validation of a rule after creation is challenging, leading to thepotential for the creation of rules that are not robust and/or accurate.In addition, when machine learning clustering is used to generate deviceclassification rules, cluster instability can also lead to reducedaccuracy and misclassifying some devices.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments herein may be better understood by referring to thefollowing description in conjunction with the accompanying drawings inwhich like reference numerals indicate identically or functionallysimilar elements, of which:

FIGS. 1A-1B illustrate an example communication network;

FIG. 2 illustrates an example network device/node;

FIG. 3 illustrates an example of the capture of traffic telemetry data;

FIG. 4 illustrates an example of a device classification service in anetwork;

FIG. 5 illustrates an example architecture for a device classificationprocess;

FIG. 6 illustrates an example architecture for device classificationrule generation and refinement;

FIG. 7 illustrates an example plot showing the percentage of unknowndevices in a network;

FIG. 8 illustrates an example architecture for refining device clusters;

FIG. 9 illustrates an example simplified procedure for generating adevice classification rule; and

FIG. 10 illustrates an example simplified procedure for adjusting adevice cluster.

DESCRIPTION OF EXAMPLE EMBODIMENTS

Overview

According to one or more embodiments of the disclosure, a deviceclassification service obtains traffic telemetry data for a plurality ofdevices in a network. The service applies clustering to the traffictelemetry data, to form device clusters. The service generates a deviceclassification rule based on a particular one of the device clusters.The service receives feedback from a user interface regarding the deviceclassification rule. The service adjusts the device classification rulebased on the received feedback.

In further embodiments, a device classification service applies a firstclustering approach to the traffic telemetry data, to form a first setof device clusters. The service provides data regarding one of thedevice clusters in the first set to a user interface. The servicereceives feedback from the user interface regarding the device clusterin the first set that indicates that the cluster should be broken up.The service applies a second clustering approach to the traffictelemetry data, to form a second set of clusters, wherein the second setof clusters comprises more device clusters than that of the first set.

Description

A computer network is a geographically distributed collection of nodesinterconnected by communication links and segments for transporting databetween end nodes, such as personal computers and workstations, or otherdevices, such as sensors, etc. Many types of networks are available,with the types ranging from local area networks (LANs) to wide areanetworks (WANs). LANs typically connect the nodes over dedicated privatecommunications links located in the same general physical location, suchas a building or campus. WANs, on the other hand, typically connectgeographically dispersed nodes over long-distance communications links,such as common carrier telephone lines, optical lightpaths, synchronousoptical networks (SONET), or synchronous digital hierarchy (SDH) links,or Powerline Communications (PLC) such as IEEE 61334, IEEE P1901.2, andothers. The Internet is an example of a WAN that connects disparatenetworks throughout the world, providing global communication betweennodes on various networks. The nodes typically communicate over thenetwork by exchanging discrete frames or packets of data according topredefined protocols, such as the Transmission Control Protocol/InternetProtocol (TCP/IP). In this context, a protocol consists of a set ofrules defining how the nodes interact with each other. Computer networksmay further be interconnected by an intermediate network node, such as arouter, to extend the effective “size” of each network.

Smart object networks, such as sensor networks, in particular, are aspecific type of network having spatially distributed autonomous devicessuch as sensors, actuators, etc., that cooperatively monitor physical orenvironmental conditions at different locations, such as, e.g.,energy/power consumption, resource consumption (e.g., water/gas/etc. foradvanced metering infrastructure or “AMI” applications) temperature,pressure, vibration, sound, radiation, motion, pollutants, etc. Othertypes of smart objects include actuators, e.g., responsible for turningon/off an engine or perform any other actions. Sensor networks, a typeof smart object network, are typically shared-media networks, such aswireless networks. That is, in addition to one or more sensors, eachsensor device (node) in a sensor network may generally be equipped witha radio transceiver or other communication port, a microcontroller, andan energy source, such as a battery. Often, smart object networks areconsidered field area networks (FANs), neighborhood area networks(NANs), personal area networks (PANs), etc. Generally, size and costconstraints on smart object nodes (e.g., sensors) result incorresponding constraints on resources such as energy, memory,computational speed and bandwidth.

FIG. 1A is a schematic block diagram of an example computer network 100illustratively comprising nodes/devices, such as a plurality ofrouters/devices interconnected by links or networks, as shown. Forexample, customer edge (CE) routers 110 may be interconnected withprovider edge (PE) routers 120 (e.g., PE-1, PE-2, and PE-3) in order tocommunicate across a core network, such as an illustrative networkbackbone 130. For example, routers 110, 120 may be interconnected by thepublic Internet, a multiprotocol label switching (MPLS) virtual privatenetwork (VPN), or the like. Data packets 140 (e.g., traffic/messages)may be exchanged among the nodes/devices of the computer network 100over links using predefined network communication protocols such as theTransmission Control Protocol/Internet Protocol (TCP/IP), User DatagramProtocol (UDP), Asynchronous Transfer Mode (ATM) protocol, Frame Relayprotocol, or any other suitable protocol. Those skilled in the art willunderstand that any number of nodes, devices, links, etc. may be used inthe computer network, and that the view shown herein is for simplicity.

In some implementations, a router or a set of routers may be connectedto a private network (e.g., dedicated leased lines, an optical network,etc.) or a virtual private network (VPN), such as an MPLS VPN, thanks toa carrier network, via one or more links exhibiting very differentnetwork and service level agreement characteristics. For the sake ofillustration, a given customer site may fall under any of the followingcategories:

1.) Site Type A: a site connected to the network (e.g., via a private orVPN link) using a single CE router and a single link, with potentially abackup link (e.g., a 3G/4G/5G/LTE backup connection). For example, aparticular CE router 110 shown in network 100 may support a givencustomer site, potentially also with a backup link, such as a wirelessconnection.

2.) Site Type B: a site connected to the network using two MPLS VPNlinks (e.g., from different service providers), with potentially abackup link (e.g., a 3G/4G/5G/LTE connection). A site of type B mayitself be of different types:

2a.) Site Type B 1: a site connected to the network using two MPLS VPNlinks (e.g., from different service providers), with potentially abackup link (e.g., a 3G/4G/5G/LTE connection).

2b.) Site Type B2: a site connected to the network using one MPLS VPNlink and one link connected to the public Internet, with potentially abackup link (e.g., a 3G/4G/5G/LTE connection). For example, a particularcustomer site may be connected to network 100 via PE-3 and via aseparate Internet connection, potentially also with a wireless backuplink.

2c.) Site Type B3: a site connected to the network using two linksconnected to the public Internet, with potentially a backup link (e.g.,a 3G/4G/5G/LTE connection).

Notably, MPLS VPN links are usually tied to a committed service levelagreement, whereas Internet links may either have no service levelagreement at all or a loose service level agreement (e.g., a “GoldPackage” Internet service connection that guarantees a certain level ofperformance to a customer site).

3.) Site Type C: a site of type B (e.g., types B 1, B2 or B3) but withmore than one CE router (e.g., a first CE router connected to one linkwhile a second CE router is connected to the other link), andpotentially a backup link (e.g., a wireless 3G/4G/5G/LTE backup link).For example, a particular customer site may include a first CE router110 connected to PE-2 and a second CE router 110 connected to PE-3.

FIG. 1B illustrates an example of network 100 in greater detail,according to various embodiments. As shown, network backbone 130 mayprovide connectivity between devices located in different geographicalareas and/or different types of local networks. For example, network 100may comprise local networks 160, 162 that include devices/nodes 10-16and devices/nodes 18-20, respectively, as well as a data center/cloudenvironment 150 that includes servers 152-154. Notably, local networks160-162 and data center/cloud environment 150 may be located indifferent geographic locations.

Servers 152-154 may include, in various embodiments, a networkmanagement server (NMS), a dynamic host configuration protocol (DHCP)server, a constrained application protocol (CoAP) server, an outagemanagement system (OMS), an application policy infrastructure controller(APIC), an application server, etc. As would be appreciated, network 100may include any number of local networks, data centers, cloudenvironments, devices/nodes, servers, etc.

The techniques herein may also be applied to other network topologiesand configurations. For example, the techniques herein may be applied topeering points with high-speed links, data centers, etc. Further, invarious embodiments, network 100 may include one or more mesh networks,such as an Internet of Things network. Loosely, the term “Internet ofThings” or “IoT” refers to uniquely identifiable objects/things andtheir virtual representations in a network-based architecture. Inparticular, the next frontier in the evolution of the Internet is theability to connect more than just computers and communications devices,but rather the ability to connect “objects” in general, such as lights,appliances, vehicles, heating, ventilating, and air-conditioning (HVAC),windows and window shades and blinds, doors, locks, etc. The “Internetof Things” thus generally refers to the interconnection of objects(e.g., smart objects), such as sensors and actuators, over a computernetwork (e.g., via IP), which may be the public Internet or a privatenetwork.

Notably, shared-media mesh networks, such as wireless networks, etc.,are often on what is referred to as Low-Power and Lossy Networks (LLNs),which are a class of network in which both the routers and theirinterconnect are constrained. In particular, LLN routers typicallyoperate with highly constrained resources, e.g., processing power,memory, and/or energy (battery), and their interconnections arecharacterized by, illustratively, high loss rates, low data rates,and/or instability. LLNs are comprised of anything from a few dozen tothousands or even millions of LLN routers, and support point-to-pointtraffic (e.g., between devices inside the LLN), point-to-multipointtraffic (e.g., from a central control point such at the root node to asubset of devices inside the LLN), and multipoint-to-point traffic(e.g., from devices inside the LLN towards a central control point).Often, an IoT network is implemented with an LLN-like architecture. Forexample, as shown, local network 160 may be an LLN in which CE-2operates as a root node for nodes/devices 10-16 in the local mesh, insome embodiments.

FIG. 2 is a schematic block diagram of an example node/device 200 thatmay be used with one or more embodiments described herein, e.g., as anyof the computing devices shown in FIGS. 1A-1B, particularly the PErouters 120, CE routers 110, nodes/device 10-20, servers 152-154 (e.g.,a network controller located in a data center, etc.), any othercomputing device that supports the operations of network 100 (e.g.,switches, etc.), or any of the other devices referenced below. Thedevice 200 may also be any other suitable type of device depending uponthe type of network architecture in place, such as IoT nodes, etc.Device 200 comprises one or more network interfaces 210, one or moreprocessors 220, and a memory 240 interconnected by a system bus 250, andpowered by a power supply 260.

The network interfaces 210 include the mechanical, electrical, andsignaling circuitry for communicating data over physical links coupledto the network 100. The network interfaces may be configured to transmitand/or receive data using a variety of different communicationprotocols. Notably, a physical network interface 210 may also be used toimplement one or more virtual network interfaces, such as for virtualprivate network (VPN) access, known to those skilled in the art.

The memory 240 comprises a plurality of storage locations that areaddressable by the processor(s) 220 and the network interfaces 210 forstoring software programs and data structures associated with theembodiments described herein. The processor 220 may comprise necessaryelements or logic adapted to execute the software programs andmanipulate the data structures 245. An operating system 242 (e.g., theInternetworking Operating System, or IOS®, of Cisco Systems, Inc.,another operating system, etc.), portions of which are typicallyresident in memory 240 and executed by the processor(s), functionallyorganizes the node by, inter alia, invoking network operations insupport of software processors and/or services executing on the device.These software processors and/or services may comprise a deviceclassification process 248, as detailed below.

It will be apparent to those skilled in the art that other processor andmemory types, including various computer-readable media, may be used tostore and execute program instructions pertaining to the techniquesdescribed herein. Also, while the description illustrates variousprocesses, it is expressly contemplated that various processes may beembodied as modules configured to operate in accordance with thetechniques herein (e.g., according to the functionality of a similarprocess). Further, while processes may be shown and/or describedseparately, those skilled in the art will appreciate that processes maybe routines or modules within other processes.

In general, device classification process 248 may execute one or moremachine learning-based classifiers to classify a device in a network,based on its corresponding network traffic. In one embodiment, deviceclassification process 248 may assess captured telemetry data regardingone or more traffic flows involving the device, to determine the devicetype associated with the device. In further embodiments, deviceclassification process 248 may classify the operating system of thedevice, based on its captured traffic telemetry data.

Device classification process 248 may employ any number of machinelearning techniques, to classify the gathered telemetry data and apply adevice type label to a device associated with the traffic. In general,machine learning is concerned with the design and the development oftechniques that receive empirical data as input (e.g., telemetry dataregarding traffic in the network) and recognize complex patterns in theinput data. For example, some machine learning techniques use anunderlying model M, whose parameters are optimized for minimizing thecost function associated to M, given the input data. For instance, inthe context of classification, the model M may be a straight line thatseparates the data into two classes (e.g., labels) such that M =a*x +b*y+c and the cost function is a function of the number of misclassifiedpoints. The learning process then operates by adjusting the parametersa,b,c such that the number of misclassified points is minimal. Afterthis optimization/learning phase, device classification process 248 canuse the model M to classify new data points, such as informationregarding new traffic flows in the network. Often, M is a statisticalmodel, and the cost function is inversely proportional to the likelihoodof M, given the input data.

In various embodiments, device classification process 248 may employ oneor more supervised, unsupervised, or semi-supervised machine learningmodels. Generally, supervised learning entails the use of a training setof data, as noted above, that is used to train the model to apply labelsto the input data. For example, the training data may include sampletelemetry data that is labeled as “iPhone 6,” or “iOS 10.2.” On theother end of the spectrum are unsupervised techniques that do notrequire a training set of labels. Notably, while a supervised learningmodel may look for previously seen patterns that have been labeled assuch, an unsupervised model may attempt to analyze the data withoutapplying a label to it. For example, supervised learning can be used tocluster devices that behave similarly to one another, based on theircaptured telemetry data. Semi-supervised learning models take a middleground approach that uses a greatly reduced set of labeled trainingdata.

Example machine learning techniques that device classification process248 can employ may include, but are not limited to, nearest neighbor(NN) techniques (e.g., k-NN models, replicator NN models, etc.),statistical techniques (e.g., Bayesian networks, etc.), clusteringtechniques (e.g., k-means, mean-shift, etc.), neural networks (e.g.,reservoir networks, artificial neural networks, etc.), support vectormachines (SVMs), logistic or other regression, Markov models or chains,principal component analysis (PCA) (e.g., for linear models),multi-layer perceptron (MLP) artificial neural networks (ANNs) (e.g.,for non-linear models), replicating reservoir networks (e.g., fornon-linear models, typically for time series), random forestclassification, or the like.

The performance of a machine learning model can be evaluated in a numberof ways based on the number of true positives, false positives, truenegatives, and/or false negatives of the model. For example, the falsepositives of the model may refer to the number of traffic flows that areincorrectly classified as associated with a particular device type(e.g., make and/or model number, operating system, etc.). Conversely,the false negatives of the model may refer to the number of trafficflows that the model incorrectly classifies as belonging to a certaindevice type. True negatives and positives may refer to the number oftraffic flows that the model correctly classifies as not being of acertain class or being of a certain class, respectively. Related tothese measurements are the concepts of recall and precision. Generally,recall refers to the ratio of true positives to the sum of truepositives and false negatives, which quantifies the sensitivity of themodel. Similarly, precision refers to the ratio of true positives thesum of true and false positives.

In some cases, device classification process 248 may assess the capturedtelemetry data on a per-flow basis. In other embodiments, deviceclassification process 248 may assess telemetry data for a plurality oftraffic flows based on any number of different conditions. For example,traffic flows may be grouped based on their sources, destinations,temporal characteristics (e.g., flows that occur around the same time orwithin the same time window, etc.), combinations thereof, or based onany other set of flow characteristics.

As shown in FIG. 3, various mechanisms can be leveraged to captureinformation about traffic in a network, such as telemetry data regardinga traffic flow. For example, consider the case in which client node 10initiates a traffic flow with remote server 154 that includes any numberof packets 302. Any number of networking devices along the path of theflow may analyze and assess packet 302, to capture telemetry dataregarding the traffic flow. For example, as shown, consider the case ofedge router CE-2 through which the traffic between node 10 and server154 flows.

In some embodiments, a networking device may analyze packet headers, tocapture telemetry data about the traffic flow. For example, router CE-2may capture the source address and/or port of host node 10, thedestination address and/or port of server 154, the protocol(s) used bypacket 302, the hostname of server 154, and/or other header informationby analyzing the header of a packet 302. Example features in thecaptured telemetry data may include, but are not limited to, TransportLayer Security (TLS) information (e.g., from a TLS handshake), such asthe ciphersuite offered, User Agent information, destination hostname,TLS extensions, etc., HTTP information (e.g., URI, etc.), Domain NameSystem (DNS) information, ApplicationlD, virtual LAN (VLAN) ID, or anyother data features that can be extracted from the observed trafficflow(s).

Further information, if available could also include process hashinformation from the process on host node 10 that participates in thetraffic flow.

In further embodiments, the device may also assess the payload of thepacket to capture information about the traffic flow. For example,router CE-2 or another device may perform deep packet inspection (DPI)on one or more of packets 302, to assess the contents of the packet.Doing so may, for example, yield additional information that can be usedto determine the application associated with the traffic flow (e.g.,packets 302 were sent by a web browser of node 10, packets 302 were sentby a videoconferencing application, etc.).

The networking device that captures the flow telemetry data may alsocompute any number of statistics or metrics regarding the traffic flow.For example, CE-2 may determine the start time, end time, duration,packet size(s), the distribution of bytes within a flow, etc.,associated with the traffic flow by observing packets 302.

As noted above, with the proliferation of IoT devices and thebring-your-own-device (BYOD) approach, it is very difficult for anadministrator to provide detailed information about each deviceconnected to the network, such as its device type (e.g., printer,iPhone, tablet, iOS 10 device, etc.). Because of the dynamic nature ofmodern networks, this type of information is not static and cannot behandled manually. However, such detailed information may be needed forproper assessment of security incidents involving a particular device,to apply a network access policy to the device, for purposes of trafficshaping of traffic involving the device, and other network operations.

FIG. 4 illustrates an example of a device classification service in anetwork, in various embodiments. As shown, network 400 may generallyinclude an endpoint device 402 (e.g., a user device, a sensor, anactuator, etc.), any number of resources 404, and any number ofnetworking devices 406 that are configured to provide connectivitybetween endpoint device 402 and resource(s) 404. For example, networkingdevices 406 may include access points, wireless LAN controllers (WLCs),switches, routers, security devices (e.g., firewalls, etc.), accesspoints (APs), and the like. Network resources 404 may includecloud-based services, specific servers or other endpoints, webpages, orany other resource with which endpoint device 402 could communicate.

Also as shown in FIG. 4 is a device classification service 408 that maybe hosted on one or more of networking devices 406 or be incommunication therewith. Service 408 may, for example, be providedthrough the execution of device classification process 248, describedabove. In general, device classification service 408 is configured totake as input telemetry data 410 captured by networking device 406regarding network traffic associated with endpoint device 402 and, basedon the captured telemetry, identify the device type 412 of endpointdevice 402. For example, device type 412 may indicate the operatingsystem (e.g., iOS, Android, etc.), manufacturer (e.g., Apple, Samsung,etc.), make (e.g., iPhone, etc.), model/version (e.g., 5s, 6, 7, etc.),function (e.g., thermostat, temperature sensor, etc.), or any otherinformation that can be used to categorize endpoint device 402.

Note that the classification of endpoint device 402 by deviceclassification service 408 can also, in some embodiments, be of varyingspecificity, depending on the telemetry data 410 available to service408 and/or its degree of confidence in a particular classification. Forexample, device classification service 408 may determine, with a highdegree of confidence, that endpoint device 402 is an Apple iPhone, butmay or may not be able to determine whether device 402 is an iPhone 5sor an iPhone 6. Accordingly, in some embodiments, service 408 may alsoreturn the confidence values for the classification label(s) in devicetype 412 to networking device 406.

The labeling of endpoint device 402 with a device type 412 by deviceclassification service 408 may initiate enforcement of one or morenetwork policies by networking device 406 with respect to endpointdevice 402. Such network policies may include, but are not limited to,security policies, network traffic or quality of service (QoS) policies,access polices, and the like. For example, as shown, assume thatendpoint device 402 sends out a resource request 414 for a particularone of resources 404. In turn, networking devices 406 may determinewhether to allow or block resource request 414 from reaching its targetresource 404, based on the policy 416 associated with the determineddevice type 412 of endpoint device 402. For example, if endpoint device402 is determined to be a smart thermostat, it may be prevented fromaccessing certain online resources, such as an email service. Similarly,if endpoint device 402 is determined to be a safety-related sensor, atraffic or QoS policy associated with device type 412 may causenetworking devices 406 to assign a higher priority to traffic fromendpoint device 402.

In general, device classification (also known as “device profiling”) toidentify the device type of a device under scrutiny has traditionallyused static rules and heuristics for the determination. In furtherembodiments, the device classification can be achieved by applying atrained machine learning-based classifier to the captured telemetry datafor an endpoint device. Such telemetry can also take the form ofinformation captured through active and/or passive probing of endpointdevices, to assign a device type and corresponding host profile to adevice. Notably, this probing may entail sending any or all of thefollowing probes:

-   -   DHCP probes with helper addresses    -   SPAN probes, to get messages in INIT-REBOOT and SELECTING        states, use of ARP cache for IP/MAC binding, etc.    -   Netflow probes    -   HTTP probes to obtain information such as the OS of the device,        Web browser information, etc.    -   RADIUS probes    -   SNMP to retrieve MIB object or receives traps    -   DNS probes to get the Fully Qualified Domain Name (FQDN)    -   etc.

A device classification service may even trigger active scanning of thenetwork and SNMP scanning when the default community string is set topublic. This can be done, for example, to retrieve the MAC address ofthe device or other types of information. Such a variety to probesallows for the gathering of a rich set of information that can be usedfor device profiling. A degree of confidence can also be assigned to anysuch device type classifications. Note also that the device profilingcan be performed at multiple points in the network, such as by wirelessLAN controllers (WLCs) in addition to, or in lieu of, a centralizedservice.

FIG. 5 illustrates an example architecture 500 for device classificationprocess 248, according to various embodiments. As shown, deviceclassification process 248 may include any or all of the followingcomponents: clustering module 502, device clusters 504, and/or a devicelabeler 506, to provide a device classification service to one or morenetworks. These components 502-506 may be implemented in a distributedmanner or implemented on a single device. In addition, some or all ofcomponents 502-506 may be implemented as part of a monitored network(e.g., at the network edge) or part of a cloud-based deviceclassification service. For example, in some implementations, acloud-based device classification service may perform centralized rulegeneration for any number of networks that perform the classificationslocally. The functionalities of the components of architecture 500 mayalso be combined, omitted, or implemented as part of other processes, asdesired.

As shown, device classification process 248 may receive device telemetrydata 508 regarding any number of devices undergoing device typeclassification. Such device telemetry data 508 may include, for example,the MAC addresses of the devices, traffic features captured from thedevices' traffic (e.g., which protocols were used, source or destinationinformation, etc.), timing information (e.g., when the devicescommunicate, sleep, etc.), and/or any other information regarding thedevices that can be used to infer their device types. For example,device telemetry data 508 may take the form of a feature vector in whicheach dimension represents the presence or absence of a certain protocolin the traffic of the device such as, but not limited to, IPv6, IPv4,IGMPv3, IGMPv2, ICMPv6, ICMP, HTTP/XML, HTTP, etc.

In turn, device classification process 248 may output a device typeclassification/label 510 for a device under scrutiny, thereby allowingthe receiving entity to apply network policies to the device, based onits device type classification(s)/label(s) 510. For example, one suchnetwork policy may cause a networking device to prevent an MRI machinefrom accessing the Internet or another resource via the network.

In various embodiments, the components 502-506 of device classificationprocess 248 may leverage active learning, to assign device typeclassification(s)/label(s) 510 to the devices under scrutiny. To do so,clustering module 502 may assign the devices under scrutiny to deviceclusters 504, based on their telemetry data 508. For example, a devicecluster 504 may include those devices that exhibit the same or similartraffic or other behavioral features. If a device type is thenassociated with a device cluster 504, device labeler 506 may apply thattype to a device as device type classification 510. In cases in whichdevice labeler 506 is unable to classify the cluster 504 with sufficientconfidence, it may send a label request to a user interface (UI),seeking active labeling of that cluster. In other words, deviceclassification process 248 may be configured to leverage activelearning, to learn the labels of unknown devices over time. Note alsothat the pool of device telemetry data 508 may be from any number ofnetworks and that device labeler 506 may seek labels for a devicecluster 504 from any number of experts across any number of networks, aswell. Once the cluster is labeled by an expert, device labeler 506 canthen apply that label to any other devices that fall within thatcluster, as well.

More formally, let D={D₁, D₂, . . . , D_(N)} denote the set of devicesseen on the one or more networks under analysis by device classificationprocess 248, each of which is identified by its MAC address or anotherunique identifier. For every device D_(i) at time t, clustering module502 may construct a feature vector X_(i,t) from the telemetry data 508for the device. Clustering module 502 may then apply a clusteringalgorithm, such as DB-scan, k-means, k-medoids, etc., to create a set ofdevice clusters 504. Let C_(t)={C_(1,t), . . . , C_(K,t)} denote thesecluster, where C_(j,t) is the j^(th) set of devices clustered togetherat time t. As would be appreciated, the number of clusters K istypically smaller, or at most equal, to the number of points N, and thecollection of clusters C defines a partition of the set of devices D. Indoing so, each device represented in a device cluster 504 may exhibitsimilar behaviors as those of the other devices in its cluster.

Clustering module 502 may perform the device clustering periodically ata relatively high frequency (e.g., hourly) or at a lower frequency(e.g., weekly). Clustering module 502 can also produce subsequentclustering either by performing new clustering from scratch or byleveraging warm-starting techniques whereby C_(t+1), is obtained byrunning the algorithm on data corresponding to that time point, butusing an initialization based on C_(t). Whether clustering module 502uses warm-starting can have a large impact on the ‘trajectory’ of theclustering and is an important design consideration.

In various embodiments, device classification process 248 may alsoreclassify a device periodically, at a predefined time, or in responseto a request to do so. For example, as the device under scrutiny usesthe network, additional device telemetry data 508 can be captured.Generally speaking, the more telemetry data regarding the behavior ofthe device, the greater the accuracy of the resulting device typeclassification/label 510. Indeed, there may be slight behavioraldifferences between devices of different types, leading deviceclassification process 248 to misclassify the device, initially, butcorrect this misclassification later on in time, as more informationabout the device becomes available.

According to various embodiments, device labeler 506 may also beconfigured to generate a device classification rule 512 for a givendevice cluster 504, based on its associated telemetry data 508,represented as positive and negative feature vectors 514, and the devicetype labels obtained from experts through active learning. For example,device labeler 506 may aggregate the labels obtained from the experts,to form a finalized device type classification label 510 for the devicecluster 504, using any number of conditions (e.g., whether a thresholdnumber of the labels agree, the majority of labels, etc.). In turn,device labeler 506 may associate this label with the telemetry data 508representative of the device cluster 504, such as the centroid of thecluster, etc.

By generating a device classification rule 512, device labeler 506 canthen use this rule to quickly assess the telemetry data for new deviceson the network(s). In addition, device labeler 506 can also deploydevice classification rule 512 to any number of Identity Service Engines(ISEs) and/or device classification services in the network(s), toperform the device classifications locally. This allows every new deviceappearing on the network and matching device classification rule 512 tobe identified with the corresponding device type.

In practice, device classification rules 512 can be specified manuallyand/or automatically generated by device classification process 248.This leads to the very real possibility of at least some deviceclassification rules 512 conflicting. For example, a manually-definedrule in a network under scrutiny may conflict with another rule that wasautomatically generated, other manually-defined rules in the network orother networks. etc.

For purposes of illustration, a device classification rule 512 may takethe form of a pair (R, L) where R is a logical statement whose freevariables are device attributes that specify whether the device typelabel L should be applied to a given device (e.g., if the attributes ofthe device satisfy R). Typically, the label L is a structured object ofthe form {manufacturer, hardware, software}, for instance, {Apple,iPhone 8, iOS 12.1.23}. In practice, R can be thought of as alow-dimensional manifold in the N-dimensional space spawned by all Nattributes that a given device can have, such as its organizationallyunique identifier (OUI), HTTP user agent, DHCP parameters, applicationusages, etc.

As noted above, device identification is without any doubt a major andcritical component of any Secure Network Access solution. For example,the Identification Service Engine (ISE) by Cisco Systems, Inc., isusually used to apply policies and consequently make use of various formof micro-segmentation. A very common approach for allocating policieslies in determining the device type. Most device classification systems(DCS) rely on simple rules and heuristics to classify devices. Thoseheuristics are not always enough for classifying consumer devices, infact, those often fail on more specific and rarer devices. For example,IoT devices are often particularly difficult to classify (because theyare usually unknown from IT policy enforcement and classificationsystems), with a multitude of medical or industrial devices that cannotbe identified by traditional systems. For those devices, foolproof ruleswhere one can clearly identify the device type in one of the messagesfrom the device's traffic usually does not exist.

Learning Robust and Accurate Rules for Device Classification fromClusters of Devices

The techniques herein introduce device rule generation techniques thatrelies exclusively on the output of a clustering engine, thuseliminating the need for expert or user supervision. Feedback about thegenerated rules can also be collected at the same time devices labelsare provided by the user. This feedback may then be used to validate orfurther refine the generated rules.

Specifically, according to various embodiments herein, a deviceclassification service obtains traffic telemetry data for a plurality ofdevices in a network. The service applies clustering to the traffictelemetry data, to form device clusters. The service generates a deviceclassification rule based on a particular one of the device clusters.The service receives feedback from a user interface regarding the deviceclassification rule. The service adjusts the device classification rulebased on the received feedback.

Illustratively, the techniques described herein may be performed byhardware, software, and/or firmware, such as in accordance with thedevice classification process 248, which may include computer executableinstructions executed by the processor 220 (or independent processor ofinterfaces 210) to perform functions relating to the techniquesdescribed herein.

Operationally, in various embodiments, FIG. 6 illustrates an examplearchitecture 600 for device classification rule generation andrefinement, according to various embodiments. At the core ofarchitecture 600 may be device labeler 506, described previously, whichis responsible for generating device classification rule(s) 512. Asshown, device labeler 506 may comprise any or all of the followingcomponents: a rule generation engine (RGE) 602, a rule validation module604, and/or a rule refinement and aggregation engine (RRAE) 606. Inaddition, in some embodiments, architecture 600 may also include aunified rule database (URD) 608. The components 602-608 may beimplemented either on a single device or in a distributed manner, inwhich case the combined devices may be viewed as a singular device forpurposes of implementing the techniques herein. For example, in someembodiments, URD 608 may be hosted in the cloud, while device labeler506 may be hosted locally in the network under scrutiny or also in thecloud. Further, the functionalities of the components of architecture600 may also be combined, omitted, or implemented as part of otherprocesses, as desired.

In various embodiments, unified rule database (URD) 608 may receive andstore device classification rules, such as device classification rule(s)512 from device labeler 506, hardcoded/manually-defined rules from othersystems, etc., maintained by any number of device classificationservices across any number of different networks. Such deviceclassification rule data may be provided to URD 608 including the ruleitself, as well as potentially associated metadata such as an identifierof the source of the rule, a timestamp of its creation, and/or anoptional indicator of confidence assigned by the creator of the rule.Consequently, URD 608 may include potentially hundreds of millions ofrules spanning millions of device types. These rules may also originatefrom various approaches, such as third-party systems, other manuallycreated rules, rules created via active labeling, third party softwaredevelopment kits (SDKs) or application programming interfaces (APIs) ofdevice vendors or the like.

An important feature of URD 608 is its extensibility: connectors andcollectors for new data sources can be easily added, even though theirrole remains always the same, that is, consuming classification rules insome arbitrary format and convert them to the universal format supportedby URD 608. Additionally, a field in URD 608 may keep track of theorigin of the rules (e.g., internal system, user-driven ML rules, . . .) from the device classification rule data, in addition to some metricstracking the number of times the rule was involved in some form ofconflict with other rules.

In various embodiments, any device that does not satisfy any of therules contained in URD 608 may be flagged as ‘UNKNOWN’ and passed on todevice classification process 248, described previously, which isconfigured to generate new device classification rules 512 throughexecution of device labeler 506. As noted, device classification process248 may repartitioning the unknown devices into groups/clusters 504 ofsimilar devices via clustering. In addition, device classificationprocess 248 may also dynamically compute the common attributes of thedevices. Both the clusters and common attributes (e.g., as computed byclustering module 502) can be used for purposes of rule generation andrefinement.

As shown, rule generation engine (RGE) 602 may be responsible forlearning device classification rules that clearly identify the devicesbelonging to a cluster, in exclusion of all the other devices. Theapproach used by RGE 602 is to create one dataset for each devicecluster 504, in which the samples are partitioned into two categories:(1) the in-cluster devices and (2) the not-in-cluster devices, thusleading to a supervised binary classification problem. This is a form ofone-vs-rest multi-class classification.

In one embodiment, RGE 602 may generate a rule based on statistics ofthe most salient common attributes, which may be included in theinformation for device cluster 504. In other words, it is possible tobuild rules by looking at the distribution of the values of some commonattributes for those devices belonging to the cluster and those that donot belong to the cluster under consideration and find which attributes'values help to tell devices apart. In another embodiment, RGE 602 maylearn a binary classifier, for example, by means of a single decisiontree, which is very useful to generate interpretable rules, or someother more complex model.

In a second phase, RGE 602 may infer a device classification rule 512 byintrospecting the model, that is, by understanding the decision taken bythe model at prediction time. In the case of a simple decision tree,this can be straightforwardly implemented by analyzing the split nodesin the tree. Said differently, the labels assigned using active labelingvia a user interface (UI) 610 may then be used by RGE 602 to train amodel capable of generating a device classification rule 512.

Regardless of the precise approach taken by RGE 602 in building a rule512, one key requirement is to generate rules 512 that are both robustand accurate. Robustness refers to how sensitive the generated rule 512is to the very dataset used to infer it, or, in other words, how likelya rule 512 is to change its exact conditions and its structure dependingon the variation of the dataset. Accuracy refers to how often the rulemakes mistakes. It is important to estimate both robustness and accuracyfor each rule 512. Those two scores can be combined into one confidencescore, sometimes referred to as the Total Certainty Factor (TCF).

In order to achieve both robustness and accuracy, given a cluster 506and its corresponding dataset, RGE 602 may generate K different datasetsby means of some resampling technique. Each of these datasets may befurther split by RGE 602 into training and test dataset and a rulelearned on the training set while being tested and scored on the testset. This yields K-number of rules with associated performancestatistics (e.g., accuracy, precision, recall, or others). At thisstage, RGE 602 may estimate the robustness of the generated rules bylooking at the common conditions and similarity in the structure of theK-number of rules. In the ideal case, the K generated rules would all beexactly the same one, giving a robustness score of 100%. Finally, RGE602 may analyze and combine the K-number of rules into one cluster-rule,whose performance is estimated by combining the statistics of theindividual rules. The so-obtained rules and their scores can be passedover to the next component(s).

It is important to notice that the techniques herein can be easilyextended to hierarchical clustering solutions, as well, where ahierarchy of rules can be learned in a way very similar to the onepresented here, on the precomputed cluster-breakdowns.

One final comment must also be made about the optimization of thehyper-parameters of the learned model of RGE 602. It is important totune the model parameters in a way that the rules inferred from thetrained model itself will not be overly complex. The reason is that, ifthe models are allowed to be arbitrarily complex, it is likely to leadto overfitting and it is equally likely that the rules generated overdifferent splits of the dataset will share a very low degree ofsimilarity, in this sense making the combination of those moredifficult. In order to prevent this, in one embodiment, RGE 602 canexplicitly constraint some of the hyper-parameters of the model, e.g.,in the case of trees, RGE 602 could constrain the maximum depth or themaximum number of leaves. In a second embodiment, RGE 602 canempirically estimate those hyper-parameters by means of approaches likehyper-opt, grid-search, and others, where the objective of theoptimization would be to guarantee that rules derived from the modelsgenerated over multiple splits would be sufficiently similar to eachother and fulfill a minimum level of similarity, making the models asprecise as possible.

In further embodiments, device labeler 508 may also include a rulevalidation module 604 that allows the users to validate and, optionally,update rules generated by RGE 602 via UI 610. To this end, the activelabeling mechanisms described previously, which offers the user theability to visualize clusters of devices that are very similar andprovide a label for all of them at once, can be further extended.Notably, in some cases, the user may now also visualize the rulegenerated by RGE 602 for this cluster (e.g., cluster 504) and may acceptor reject it with some additional feedback. More specifically, rulevalidation module 604 may send rule data 612 to UI 610 regarding therule generated by RGE 602 and, in turn, receive feedback 614 from theuser regarding the proposed rule. This can be performed, for example, inconjunction with RGE 602 requesting a label from the user for cluster504, through active labeling, to generate the rule.

In one embodiment, the user can provide feedback 614 to rule validationmodule 604 by choosing one or more options among some predefined set ofpossible feedback, for example:

-   -   [ ] Rule is too complicated (as in, there are too many        conditions)    -   [ ] Rule is too simplistic (as in, the conditions presented are        too general)    -   [ ] Rule is allowing different manufacturers

In another embodiment, rule validation module 604 may allow the user ofUI 610 to modify the rule generated by RGE 602 on-the-fly, eitherremoving some of the conditions in the presented rule or adding somemore conditions, to be picked among a series of suggested ones,previously computed by the system. As the user modifies the proposedrule, the accuracy and robustness scores associated with the rule wouldchange with estimates of how the change will impact the ruleperformance.

In some cases, the user may submit the validated rule at the same timeas the cluster label. This collected feedback 614 on the rule will beinstrumental to the operation of rules refinement and aggregation engine(RRAE) 606.

In general, RRAE 606 analyses the collected labels, rules, and rules'feedback from RGE 602 and rule validation module 604, to further refinethe rule generated by RGE 602 into a finalized device classificationrule 512. RRAE 606 may perform this rule refinement in two stages, asdetailed below.

First, in case the proposed rule is rejected via UI 610, and feedback614 is provided back to rule validation module 604, RRAE 606 may usehints contained in feedback 614 to refine the rule. For example, in oneembodiment the provided feedback 614 can come in the form of a commentselected among a fixed set of options, e.g. say the specific feedback is“The rule is too complex, there are too many conditions,” then RRAE 606will prune the originally generated rule.

In a second embodiment, the collected feedback 614 could come in theform of a user-modified rule, in which case, the role of RRAE 606 wouldbe to compute the actual performance of the new rule and possibly findan interpolation between the originally generated rule and theuser-modified one that maximizes performance. The feedback 614 may alsobe integrated in a database to adjust how RGE 602 generating rules forthis user in the future. Indeed, if the user is generally finding therules generated by RGE 602 too complex, all future rules may besimplified, thus adjusting the system globally.

RRAE 606 may also try to merge rules that refer to the same device type.This can be achieved by looking at the labels provided across allclusters. To better understand why this step might sometimes be needed,it is important to understand that the clustering algorithm used byclustering module 502 can generate multiple clusters for devicesbelonging to the same device type. As a matter of fact, the clusteringmay end up separating devices that are actually the same device typeinto two or more clusters. This may occur because of different trafficbehavior, different versions or other subtle differences. In thiscontext, the role of RRAE 606 might be to merge multiple rules comingfrom different clusters that have been labeled with the same devicetype.

In one embodiment, the rule merging by RRAE 606 could be as simple asconcatenating all of the individual clusters' rules by means of thelogical OR operator, to generate a finalized device classification rule512.

In another embodiment, RRAE 606 can take more sophisticated approaches,to merge rules. For example, in case rules are generated by RGE 602 fromtrees, it may be possible to merge rules by means of principledapproaches for merging decision trees. Not only, once all the trees aremerged, the final tree (corresponding to the final rule) could bepruned, resulting in a simpler rule. Note also that it would beimportant to track the performance of the final rule as it gets pruned,making sure the pruning keeps going only until a certain minimumrequired precision is hit.

In one last step, RRAE 606 may submit the so obtained rules to URD 608,thereby extending the knowledge base and allowing for the cross-systemdeployment and comparison of device classification rules. For example,by leveraging URD 608, a rule 512 generated for a newly seen device typecould be used in other networks to label devices of the same type.Similarly, URD 608 can be used to compare rules generated acrossdifferent deployments, to help further refine the rules and/or resolveconflicts.

A working prototype of the above rule generation and validationtechniques was constructed. To further illustrate the workings of thesetechniques, the prototype generated a first cluster, Cluster A, thatincluded 91 devices as follows:

Common attributes:

-   -   OUI: Cisco Systems, Inc (100.0%)    -   isHTTPServer: http (1.098%)    -   networkElementType: Device Type#All Device Types#WS-C4510RE        (100.0%)    -   DHCPClassIdentifier: Cisco Systems, Inc. IP Phone CP-8865        (100.0%)    -   CDPPlatform: Cisco IP Phone 8865 (100%)    -   CDPVersion: sip8845_65.12-1-1SR1-4.1oads (98.90%)    -   DHCPParameterRequestList: 1, 42, 66, 6, 3, 15, 150, 35 (100.0%)    -   Accordingly, the prototype generated the following rule for        Cluster A:    -   {DHCP-fingerprint==“1, 42, 66, 6, 3, 15, 150, 35”}    -   AND    -   {    -   {DHCP-Class-ID==“Cisco Systems, Inc. IP Phone CP-8865”}    -   OR    -   {CDP-Cache-Platform==“Cisco IP Phone 8865”}    -   }

The above rule exhibits both a robustness score and precision score of100%. Thus, we can assume that the user would accept the rule andprovide as a label the following:

-   -   Label: “Manufacturer: Cisco Systems Inc., Model: IP Phone        CP-8865”

The prototype also generated a second cluster, Cluster B, that included195 devices, as follows:

Common attributes:

-   -   OUI: Cisco Systems, Inc (100.0%)    -   isHTTPServer: http (4.102%)    -   networkElementType: Device Type#All Device Types#WS-C4510RE        (100.0%)    -   DHCPClassIdentifier: Cisco Systems, Inc. IP Phone CP-8865        (100.0%)    -   CDPPlatform: Cisco IP Phone 8865 (100%)    -   CDPVersion: sip8845_65.12-1-1SR1-4.1oads (89.74%)    -   DHCPParameterRequestList: 1, 3, 6, 15, 35, 66, 150, 2, 7, 42,        43, 58, 59, 159, 160 (100.0%)

From the above cluster, the prototype generated the following rule forCluster B:

{DHCP-fingerprint = = “1, 3, 6, 15, 35, 66, 150, 2, 7, 42, 43, 58, 59,159, 160”} AND { {DHCP-Class-ID = = “Cisco Systems, Inc. IP PhoneCP-8865”} OR {CDP-Cache-Platform = = “Cisco IP Phone 8865”} }

The above rule for Cluster B also exhibits robustness and precisionscores of 100%. Thus, we can also assume that the user will accept therule and provide the following label:

Label: “Manufacturer: Cisco Systems Inc., Model: IP Phone CP-8865”

Given the above reported rules and labels from UI 610, RRAE 606 caneasily figure out by inspecting the rules that those rules refer to thesame device type (e.g., by matching the provided labels). By analyzingthe exact conditions and the specific structure of the two rules, RRAE606 can finally produce the final rule 512 and its stats, as follows,which will be eventually deployed to URD 608:

{ {DHCP-fingerprint = = “1, 42, 66, 6, 3, 15, 150, 35”} OR{DHCP-fingerprint = = “1, 3, 6, 15, 35, 66, 150, 2, 7, 42, 43, 58, 59,159, 160”} } AND { {DHCP-Class-ID = = “Cisco Systems, Inc. IP PhoneCP-8865”} OR {CDP-Cache-Platform = = “Cisco IP Phone 8865”} }

Referring again to FIG. 5, while the above approaches introduce anapproach to generate device classification rules 512, another importantfactor that can influence the robustness and accuracy of the resultingrule 512 is how the devices are clustered by clustering module 502.

In some cases, the clustering algorithm of clustering module 502 can beoptimized without ground truth (i.e., the type of the observed devices).The key idea behind this is that an effective clustering algorithm musttrade off a notion of stability (that is, devices clustered together attime t shall remain clustered together at time t+1, t+2, . . . ) andrichness (that is, different devices shall be grouped into differentclusters). More specifically, the learning system can utilize any stableattributes of the devices observed on a real network (e.g., MAC address,OUI) in order to optimize the feature representation used for clusteringthese devices. In turn, clustering module 502 may combine areconstruction loss, which tends to favor very detailed anddevice-specific representations, and a classification loss, which forcesthe representation to remain stable across time and across devices thatshare the same stable attributes.

Still the main challenge comes from the fact that, while providing morestability, large clusters will group more (potentially different)devices, thus yielding less accurate labels. On the other hand, smallclusters lead to more accurate (specific) labels at the cost of possiblyless stability or generalization power and more work required from theuser to provide labels (since there are more clusters).

FIG. 7 illustrates an example plot 700 that shows the proportion ofunknown devices comprised by the first 20 clusters by size that weregenerated by the prototype. As shown, it can be seen that the top 4clusters actually cover more than 80% of the unknown devices in the‘Cisco-IT’ test network. Similarly, the top 7 clusters comprised morethan 90% of the unknown devices in the ‘SJSU’ test network.

Accordingly, further aspects of the techniques herein introduce anapproach where large clusters are potentially and incrementally brokendown based on the characteristics of the devices in the clusteraccording to user input. In contrast with an approach that tries tooptimize for stability and richness, the proposed approach specificallyoptimizes for large clusters, with the known effect that large clusterstend to regroup different devices while bringing great stability.

FIG. 8 illustrates an example architecture 800 for refining deviceclusters, according to various embodiments. At the core of architecture800 may be clustering module 502, described previously with respect toFIG. 5, which is responsible for generating device classificationrule(s) 512. As shown, device labeler 506 may comprise any or all of thefollowing components: a large and stable clusters generator (LSCG) 802,a cluster validation module 804, and/or a recommendation module 806. Thecomponents 802-806 may be implemented either on a single device or in adistributed manner, in which case the combined devices may be viewed asa singular device for purposes of implementing the techniques herein.Further, the functionalities of the components of architecture 800 mayalso be combined, omitted, or implemented as part of other processes, asdesired.

In various embodiments, large and stable clusters generator (LSCG) 802is configured to generate large, stable clusters of devices based ondevice telemetry data 508. In one embodiment, LSCG 802 could base therepartition of the devices into large clusters on a simple look up ofsome fundamental properties of the devices, such as their OUIs, theiroperating systems, or other very stable attributes associated to thedevices themselves, and unrelated to the behavior of the user operatingthe devices. In this case, LSCG 802 may group/cluster devices basedsolely on the values taken by one or more key attributes. For example,considering only the OUI, LSCG 802 may generate one cluster for all“Apple Inc.” devices, one for all “Samsung Electronics” devices, and soon.

In a second embodiment, LSCG 802 could rely on a clustering algorithmexplicitly optimized to achieve large, stable clusters. LSCG 802 could,for example, use a density-based approach, such as DBSCAN, OPTICS orothers, which allow for explicitly optimizing for large clusters. Thosealgorithms mentioned above rely on one key parameter, referred to in theliterature as MinSamples, the minimum number of samples required in eachcluster. In this case, when optimizing the hyperparameters by means ofapproaches such as, grid search, Hyperopt, etc., one could guaranteelarger clusters by limiting the allowed values for MinSamples to belarger than a predetermined large value V. In this way, LSCG 802 couldrequire that the clusters have a large minimum size, while stillallowing any other parameter to be optimized with respect to some othermetric of interest. For example, LSCG 802 could maximize the purity ofclusters, in case labels for the devices are available. Alternatively,LSCG 802 could maximize the numbers of clusters, provided they allcontain a number of devices larger than the above specified value V.

Another potential component of architecture 800 is cluster validationmodule 804 that allows for user input so as to specify clusters forwhich greater granularity (and thus accuracy) is required, according tovarious embodiments. For example, cluster validation module 804 mayprovide cluster data 808 to UI 610 and, in turn, receive feedback 810from the user of UI 610 regarding the clustering approach.

In one embodiment, cluster validation module 804 may identify clustersfrom LSCG 802 that require greater granularity using a policy-basedengine. For example, feedback 810 for the cluster data 808 of a largecluster may include that all devices matching a specific OUI valueshould be subject to clustering using an objective function whoseobjective is to optimize accuracy. Just for the sake of illustration, anetwork administrator using UI 610 may require an approach leading tomore accurate clusters (at the risk of having many clusters to labelwith potential instability) for devices related to IoT (criticaldevices), whereas grouping all Apple devices may be perfectlyacceptable, in which case grouping all Apple devices into a singlecluster (with MacBook, iPhone, iPad, . . . ) may be perfectlyacceptable.

In a second embodiment, cluster validation module 804 may allow the userof UI 610 to manually tag the cluster that offers a simple and intuitiveworkflow for this task, via feedback 810. When inspecting a cluster,cluster validation module 804 could provide additional context relatedto several devices in the cluster (potentially at the edge of thecluster) as part of cluster data 808, in order for the user of UI 610 toinstruct clustering module 502 via feedback 810 to break up the clusterfurther. For instance, the user may provide as feedback 810 a givenattribute value or a combination thereof to select devices to beclustered separately.

In another embodiment, cluster validation module 804 may itself make asmart selection of devices in the clusters so as to select a set of Ndevices in a cluster along with the additional context, while trying tomaximize the intra-cluster distance between those N candidates, or thedistance to the centroid, etc. This can be achieved by using aclustering algorithm that provides hierarchical structures, such asOPTICS.

Such a break-up approach could continue until required by the user of UI610 via feedback 810. Note that a user may require to merge clustersback, if the label accuracy has not dramatically improved with thecluster break-up, or if the new set of clusters leads to too muchinstability. Indeed, depending on the features from device telemetrydata 508 used for clustering, devices may be subject to instability(e.g., moving from one cluster to another as features tend to vary).

Upon performing cluster break-up, cluster validation module 804 mayprovide some metrics related to the inter-cluster movements resultingfrom the cluster break-up back to UI 610. The user may then decide toautomatically regroup the clusters, making a tradeoff between improvedaccuracy of the labels and lack of stability. Another criterion might berelated to the number of new clusters resulting from the clusterbreak-up.

Cluster validation module 804 may also allow further refinements in there-grouping only to a point that makes sense, in further embodiments.That is, cluster validation module 804 may offer the user of UI 610 theability to further refine the clustering, as indicated in cluster data808, when the number N of newly generated clusters is below a definedthreshold. Notably, too high a number of clusters implies that theclusters are too small, with the extreme case being clusters thatinclude only one device. In other words, the number of resulting newclusters N may be not worth the gain in terms of label accuracy. Thus, afurther function of cluster validation module 804 is to estimate anupper bound UB for the number of refined sub-clusters N obtained in theprogressive break-up of an original large stable cluster.

In one embodiment, cluster validation module 804 may estimate UB asbeing proportional to the number of samples in the original big clusterfrom LSCG 802. For example, say UB is fixed to be 5% of the number ofdevices in the large stable cluster. In this case, consider a largestable cluster C which groups 12,000 devices, UB may be equal to12,000×0.05=600, meaning that cluster validation module 804 will onlyallow for the refining of the clustering until 600 new clusters aregenerated. The maximum number of clusters allowed being limited toUB=600 implies that clustering module 502 allows, at its finestregrouping, to have an average cluster size of 12,000/600=20 devices.

In another embodiment, cluster validation module 804 could impose aminimum number of devices per cluster, thus indirectly inducing amaximum number of clusters UB.

Another component of architecture 800 may be recommendation module 806that takes as input the recommendations from feedback 810 across alldeployments and/or Uls, store them. In turn, recommendation module mayaugment the cluster data 808 provided to UI 610 with suggested clusterbreak-ups/divisions as a function of previous choices. Indeed, it islikely that different users have similar policy and securityrequirements.

In another embodiment, aggregated statistics about cluster break-ups indifferent regions of the space may be retrofitted to the clusteringalgorithm of LSCG 802 (e.g., DB-SCAN, OPTICS), to optimize itsparameters so that the resulting clusters match closely the structuresuggested by user-defined break-ups.

Said differently, the above clustering mechanism introduces ahierarchical approach whereby unknown devices are first grouped into arough set of larges clusters, optimizing for stability of the clusterassignments. In a second phase, clusters requiring more accurate labels(according to policies and/or user input) may be broken down using adifferent objective function so as to refine labels and improveaccuracy. The user decision on whether to break a cluster up may beeased by performing automatic cluster inspection, selecting candidatedevices in a cluster and providing additional context to the user.Mechanisms are also specified to perform automatic cluster regroupingshould high instability and/or lack of label accuracy improvement bedetected.

FIG. 9 illustrates an example simplified procedure for generating adevice classification rule, in accordance with one or more embodimentsdescribed herein. For example, a non-generic, specifically configureddevice (e.g., device 200) may perform procedure 900 by executing storedinstructions (e.g., process 248), to provide a device classificationservice to one or more networks. The procedure 900 may start at step905, and continues to step 910, where, as described in greater detailabove, the device classification service may obtain traffic telemetrydata for a plurality of devices in a network. For example, the telemetrydata may indicate the features/characteristics of the traffic sent bythe devices such as, but not limited to, the protocols used, packetstatistics (e.g., size, etc.), timing information, endpoint information(e.g., destination port, address, etc.), and/or any other informationthat can be obtained through inspection of the traffic.

At step 915, as detailed above, the device classification service mayapply clustering to the traffic telemetry data, to form device clusters.As would be appreciated, doing so results in clusters of devices thatexhibit similar traffic behaviors (e.g., the protocols used, timing,etc.). In some embodiments, the service may perform this stepiteratively by applying a first clustering approach to the traffictelemetry data, to form a first set of device clusters, providing dataregarding one of the device clusters in the first set to a userinterface, receiving feedback from the user interface regarding thedevice cluster in the first set that indicates that the cluster shouldbe broken up, and applying a second clustering approach to the traffictelemetry data, to form a second set of clusters, wherein the second setof clusters comprises more device clusters than that of the first set.For example, the first and second clustering approaches may usedifferent objective functions, with the first creating fewer, but largerclusters, than that of the second.

At step 920, the device classification service may generate a deviceclassification rule based on a particular one of the device clusters, asdescribed in greater detail above. In general, a device classificationrule may comprise any number of conditions that need to be met. Forexample, one such condition may specify the DHCP parameters that arecommon to the cluster. Such a rule can then be used to assign a devicetype label to a device in the network based on the traffic telemetrydata associated with that device (e.g., if the characteristics of itstraffic match the rule). For example, the service may leverage activelabeling to associate a device type label to the rule and then use therule to classify new devices in the network. Such a label may, forexample, indicate one or more of: a manufacturer of the device, a modelof the device, or a version associated with the device.

At step 925, as detailed above, the device classification service mayreceive feedback from a user interface regarding the deviceclassification rule. Such feedback may, for example, indicate that therule has too many conditions (e.g., the rule is too complicated), therule has too few conditions (e.g., the rule is too simplistic), or therule allows for different device manufacturers, which could lead to themisclassification of devices.

At step 930, the device classification service may adjust the deviceclassification rule based on the received feedback, as described ingreater detail above. In some cases, for example, this may entail thedevice adding or removing conditions from the rule. In furtherembodiments, the service may also merge the rule with another existingrule, to form a merged rule. This may be performed in the case of bothrules referring to the same device type (label), for example. Procedure900 then ends at step 935.

FIG. 10 illustrates an example simplified procedure for adjusting adevice cluster, in accordance with one or more embodiments describedherein. For example, a non-generic, specifically configured device(e.g., device 200) may perform procedure 1000 by executing storedinstructions (e.g., process 248), to provide a device classificationservice to one or more networks. The procedure 1000 may start at step1005, and continues to step 1010, where, as described in greater detailabove, the service may apply a first clustering approach to the traffictelemetry data, to form a first set of device clusters. For example, thedevice may attempt to first form the largest device clusters possiblethat are still stable.

At step 1015, as detailed above, the device classification service mayprovide data regarding one of the device clusters in the first set to auser interface. In some instances, this data may indicate the attributesof the devices in the cluster, such as the variousfeatures/characteristics of their traffic. In one embodiment, the datamay also include a recommendation that one of the clusters should bebroken up, such as based on prior user feedback.

At step 1020, the device classification service may receive feedbackfrom the user interface regarding the device cluster in the first setthat indicates that the cluster should be broken up, as described ingreater detail above. Indeed, while large clusters may be desirable,increased cluster granularity (e.g., smaller, more numerous clusters)may also lead to greater accuracy of any resulting classification rulefrom the cluster.

At step 1025, as detailed above, the device classification service mayapply a second clustering approach to the traffic telemetry data, toform a second set of clusters. In various embodiments, the second set ofclusters comprises more device clusters than that of the first set,meaning that the second set comprises clusters of greater granularitythan that of the first set. In general, the first and second approachesmay differ by one or more of: their parameters (e.g., objectivefunctions, thresholds, etc.), their input datasets, and/or theirclustering algorithms. For example, the second clustering approach mayuse a different objective function than that of the first, to morefinely cluster the devices. Procedure 1000 then ends at step 1030.

It should be noted that while certain steps within procedures 900-1000may be optional as described above, the steps shown in FIGS. 9-10 aremerely examples for illustration, and certain other steps may beincluded or excluded as desired. Further, while a particular order ofthe steps is shown, this ordering is merely illustrative, and anysuitable arrangement of the steps may be utilized without departing fromthe scope of the embodiments herein. Moreover, while procedures 900-1000are described separately, certain steps from each procedure may beincorporated into each other procedure, and the procedures are not meantto be mutually exclusive.

The techniques described herein, therefore, allow for learning robustand accurate device classification rules. In addition, the techniquesherein can be used to appropriately sized clusters for purposes of rulegeneration and device labeling.

While there have been shown and described illustrative embodiments thatprovide for learning device classification rules and classifyingdevices, it is to be understood that various other adaptations andmodifications may be made within the spirit and scope of the embodimentsherein. For example, while certain embodiments are described herein withrespect to using certain models for purposes of device typeclassification, the models are not limited as such and may be used forother functions, in other embodiments. In addition, while certainprotocols are shown, other suitable protocols may be used, accordingly.

The foregoing description has been directed to specific embodiments. Itwill be apparent, however, that other variations and modifications maybe made to the described embodiments, with the attainment of some or allof their advantages. For instance, it is expressly contemplated that thecomponents and/or elements described herein can be implemented assoftware being stored on a tangible (non-transitory) computer-readablemedium (e.g., disks/CDs/RAM/EEPROM/etc.) having program instructionsexecuting on a computer, hardware, firmware, or a combination thereof.Accordingly, this description to be taken only by way of example and notto otherwise limit the scope of the embodiments herein. Therefore, it isthe object of the appended claims to cover all such variations andmodifications as come within the true spirit and scope of theembodiments herein.

What is claimed is:
 1. A method, comprising: obtaining, by a deviceclassification service, traffic telemetry data for a plurality ofdevices in a network; applying, by the service, clustering to thetraffic telemetry data, to form device clusters; generating, by theservice, a device classification rule based on a particular one of thedevice clusters, the device classification rule comprising one or moreconditions needed to be met to assign a device label to a device in thenetwork; receiving, at the service, feedback from a user interfaceregarding the device classification rule, the feedback indicative ofwhether the one or more conditions accurately assign the device label tothe device; and adjusting, by the service, the device classificationrule based on the received feedback, wherein adjusting the deviceclassification rule based on the received feedback comprises:determining that the rule refers to a plurality device types; andmodifying the one or more conditions so that the device classificationrule does not assign the device label to one of the plurality devicetypes.
 2. The method as in claim 1, wherein the adjusted deviceclassification rule is used to assign the device type label to thedevice in the network based on the traffic telemetry data associatedwith that device.
 3. The method as in claim 2, wherein the device typelabel is indicative of one or more of: a manufacturer of the device towhich the label was assigned, a model of that device, or a versionassociated with that device.
 4. The method as in claim 1, wherein thefeedback indicates one of: the rule having too many conditions, the rulehaving too few conditions, or the rule allowing different manufacturers.5. The method as in claim 1, further comprising: deploying, by theservice, the adjusted device classification rule to a router or switch,wherein the router or switch uses the adjusted device classificationrule to classify a particular device.
 6. The method as in claim 1,further comprising: providing, by the service, the adjusted deviceclassification rule for storage by a cloud-based unified rule database.7. The method as in claim 1, further comprising: receiving, by theservice, additional traffic telemetry data for the plurality of devicesin the network; and applying, by the service, subsequent clustering tothe additional traffic telemetry data, to form additional deviceclusters at a periodic time or a predefined time.
 8. An apparatus,comprising: one or more network interfaces to communicate with one ormore networks; a processor coupled to the network interfaces andconfigured to execute one or more processes; and a memory configured tostore a process executable by the processor, the process when executedconfigured to: obtain traffic telemetry data for a plurality of devicesin a network; apply clustering to the traffic telemetry data, to formdevice clusters; generate a device classification rule based on aparticular one of the device clusters, the device classification rulecomprising one or more conditions needed to be met to assign a devicelabel to a device in the network; receive feedback from a user interfaceregarding the device classification rule, the feedback indicative ofwhether the one or more conditions accurately assign the device label tothe device; and adjust the device classification rule based on thereceived feedback, wherein adjusting the device classification rulebased on the received feedback comprises: determining that the rulerefers to a plurality device types; and modifying the one or moreconditions so that the device classification rule does not assign thedevice label to one of the plurality device types.
 9. The apparatus asin claim 8, wherein the adjusted device classification rule is used toassign the device type label to the device in the network based on thetraffic telemetry data associated with that device.
 10. The apparatus asin claim 9, wherein the device type label is indicative of one or moreof: a manufacturer of the device to which the label was assigned, amodel of that device, or a version associated with that device.
 11. Theapparatus as in claim 8, wherein the feedback indicates one of: the rulehaving too many conditions, the rule having too few conditions, or therule allowing different manufacturers.
 12. The apparatus as in claim 8,wherein the process when executed is further configured to: deploy theadjusted device classification rule to a router or switch, wherein therouter or switch uses the adjusted device classification rule toclassify a particular device.
 13. The apparatus as in claim 8 whereinthe process when executed is further configured to: provide the adjusteddevice classification rule for storage by a cloud-based unified ruledatabase.
 14. The apparatus as in claim 8 wherein the process whenexecuted is further configured to: receive additional traffic telemetrydata for the plurality of devices in the network; and apply subsequentclustering to the additional traffic telemetry data, to form additionaldevice clusters at a periodic time or a predefined time.
 15. A tangible,non-transitory, computer-readable medium storing program instructionsthat cause a device classification service to execute a processcomprising: obtaining, by the device classification service, traffictelemetry data for a plurality of devices in a network; applying, by theservice, clustering to the traffic telemetry data, to form deviceclusters; generating, by the service, a device classification rule basedon a particular one of the device clusters, the device classificationrule comprising one or more conditions needed to be met to assign adevice label to a device in the network; receiving, at the service,feedback from a user interface regarding the device classification rule,the feedback indicative of whether the one or more conditions accuratelyassign the device label to the device; and adjusting, by the service,the device classification rule based on the received feedback, whereinadjusting the device classification rule based on the received feedbackcomprises: determining that the rule refers to a plurality device types;and modifying the one or more conditions so that the deviceclassification rule does not assign the device label to one of theplurality device types.
 16. The computer-readable medium as in claim 15,wherein the adjusted device classification rule is used to assign thedevice type label to the device in the network based on the traffictelemetry data associated with that device.
 17. The computer-readablemedium as in claim 16, wherein the device type label is indicative ofone or more of: a manufacturer of the device to which the label wasassigned, a model of that device, or a version associated with thatdevice.
 18. The computer-readable medium as in claim 15, wherein thefeedback indicates one of: the rule having too many conditions, the rulehaving too few conditions, or the rule allowing different manufacturers.19. The computer-readable medium as in claim 15, the process furthercomprising: deploying, by the service, the adjusted deviceclassification rule to a router or switch, wherein the router or switchuses the adjusted device classification rule to classify a particulardevice.
 20. The computer-readable medium as in claim 15, the processfurther comprising: providing, by the service, the adjusted deviceclassification rule for storage by a cloud-based unified rule database.